CN107666850A - Fiber Management in the Medical Device Backend - Google Patents

Abstract

A flexible tool comprising an optical fiber including a proximal region, a distal region, an intermediate portion between the proximal region and the distal region, and a bend region between the proximal region and the intermediate portion, wherein the intermediate portion is constrained to have a single degree of freedom that translates substantially along an axis defined by the optical fiber at the intermediate portion. Optical fibers may be used to provide shape sensing of the flexible tool.

Description

Fiber Management in the Medical Device Backend

technical field

This application claims priority from US Provisional Patent Application No. 62/155,655, the entire contents of which are incorporated herein by reference.

Background technique

Various techniques for detecting the shape of optical fibers and their applications are known.

US Patent No. 7,781,724 (incorporated herein by reference in its entirety) discloses a fiber optic sensor capable of determining the position and shape of an object. This patent discloses a fiber optic position and shape sensing device and method for determining the position and shape of an object using a fiber optic device comprising at least two fiber optic cores and having a set A fiber Bragg grating array coupled with a frequency domain reflectometer within it.

US Patent No. 7,720,322 (incorporated herein by reference in its entirety) discloses a shape sensing system with optical fibers to determine the position and orientation of one link relative to another link in a kinematic chain. The interrogator senses the strain in the fiber as the joint in the kinematic chain moves. The sensed strain is used to output Cartesian position and orientation.

US Patent No. 8,460,236 (incorporated herein by reference in its entirety) discloses methods, systems and apparatus for sensing or measuring the shape or position and shape of one or more components of a formable elongate medical device.

US Patent No. 8,672,837 (incorporated herein by reference in its entirety) also discloses methods, systems and apparatus for sensing or measuring the shape or position and shape of one or more components of a formable elongate medical device.

Contents of the invention

Shape sensing using fiber optics can be useful in applications where knowledge of the shape and/or position of a tool is required. For example, medical devices are often inserted into the human or animal body and guided through blood vessels or the digestive tract. The shape or location of a tool can provide useful information to the program using that tool. While catheters are frequently discussed herein, it should be understood that the preceding description is applicable to any type of implement that bends and/or changes shape. In fact, the present disclosure can be applied to any structure of shape or endpoint location of interest. For example, an articulated robotic arm can bend and/or change shape. The present disclosure can be applied to other flexible structures such as morphing antennas, morphing wings, tethers for remotely operating vehicles and sonar arrays. In fact, any structure that is concerned with shape or endpoint location can be considered a tool according to this technique.

With the practical implementation of shape sensing using optical fibers within the tool, the central part of the tool can be used for the functional aspects of the tool. For example, FIG. 1 shows a cross-sectional or end view of a tool 10 described as a catheter. A central portion of catheter 10 is a lumen 12 that allows passage of another tool or substance through catheter 10 . Catheter 10 may include one or more wires 14 arrayed around lumen 12 to manipulate the shape of catheter 10 . The position of the lumen 12 and wire 14 may indicate that the optical fiber 100 used to sense the shape of the catheter 10 is offset from the center or neutral axis 16 of the catheter 10 .

In some applications, the end of optical fiber 100 may be fixed relative to the end of catheter 10 . For example, it may be advantageous to secure the end of the optical fiber 100 relative to the end of the catheter 10 if it is desired to detect the position of the catheter end. There may be other reasons for securing the end of the optical fiber 100 relative to the end of the catheter 10 . For example, the end of the optical fiber 100 may be the most convenient location to attach the optical fiber 100 to the catheter 10 .

Certain considerations may arise if the optical fiber 100 is offset from the neutral axis 16 . For example, FIG. 2 shows a side view of catheter 10 in which optical fiber 100 is shown as a dashed line offset from the center of catheter 10 . The length of the optical fiber 100 corresponding to the length of the catheter 10 is axially aligned with the length of the catheter 10 when the catheter 10 is straight.

FIG. 3 shows the catheter 10 bent upwards or from the neutral axis 16 towards the optical fiber 100 . In the case of bending in this direction, the position 102 of the fiber 100 corresponding to the end of the catheter 10 is forced outwards by a distance D relative to the end of the catheter 10 because the length of the fiber 100 does not change.

FIG. 4 shows the catheter 10 bent in the opposite orientation to that shown in FIG. 3 . By such bending, the location 102 of the optical fiber 100 is drawn a distance D into the catheter 10 .

As shown in these figures, the optical fiber 100 moves relative to the catheter 10 along its length as the catheter 10 changes shape. Thus, the shape of the fiber may not exactly correspond to the shape of the catheter 10 (eg, because the bend radius may be different and a portion of the fiber 100 may extend from or be drawn into the catheter 10), and correlations may be used to account for any differences. However, the manner in which the optical fiber 100 is constrained to the catheter 10 can affect the correlation. For example, as shown in Figure 5, if the fiber is one meter long, and the position 102 of the fiber 100 is misaligned from the catheter 10 by a tenth of a degree, then any sensed position of the end of the catheter 10 will be off by 1.75 millimeters. Errors can be magnified if the catheter 10 and optical fiber 100 have any bends.

Additionally, it may be important to limit the strain applied to the optical fiber 100 . For example, the strain in the fiber 100 is used to determine the shape of the fiber 100 as explained in one or more of the patents cited above. If the fiber 100 is stretched (instead of or in addition to being bent to conform to the shape of the catheter 10 ) as a result of being secured to the catheter 10 , the strain from the stretching can cause strain affecting the signal used to calculate the shape of the fiber 100 . Also, from a mechanical standpoint, too much strain placed on the fiber 100 can cause the fiber to break.

One aspect of the present technology addresses one or more problems of the prior art.

One aspect of the present technology includes a flexible tool comprising: an optical fiber including a proximal end, a distal end, an intermediate portion between the proximal end and the distal end, and an optical fiber at the proximal end An adjustable bend between the first portion and the middle portion, wherein the middle portion is constrained to have a single degree of freedom of translation substantially along an axis defined by the optical fiber at the middle portion.

In an example, (a) the flexible tool further includes a body having a flexible portion and a free end, wherein a portion of the optical fiber is located within the body, and the distal end is fixed relative to the body at or near the free end; ( b) the body includes a neutral axis, and the optical fiber is disposed within the body, wherein the optical fiber is offset from the neutral axis and is substantially parallel to the neutral axis at least at the flexible portion; (c) the distal end is reversible relative to the proximal end Moves with three translational degrees of freedom; (d) the distal end is movable with two rotational degrees of freedom relative to the proximal end; (e) the distal end is movable with three translational degrees of freedom relative to the proximal end and two rotational degrees of freedom; (f) the flexible part includes a flexible joint; (g) the flexible tool further includes a rigid member, wherein the middle part is fixed within the rigid member; (h) the rigid member is substantially along the axial direction of the cylinder A cylinder having a length of flat surface; (i) the flexible tool further comprising: two cylindrical pins having central axes substantially parallel to each other and together defining a first plane; a third cylindrical pin which having a central axis in a second plane substantially parallel to and offset from the central axes of the two cylindrical pins and substantially perpendicular to the first plane; a ball and a spring, wherein the first Three pins and balls contact the rigid member along the flat surface, two cylindrical pins contact the rigid member along the axial length of the cylinder but not on the flat surface, and a spring contacts the rigid member to push the rigid member against the two cylinders , the third cylinder and the ball contact; (j) the rigid member includes a block having a first planar surface defined by a first plane and a second planar surface defined by a second plane along a single degree of freedom Substantially parallel lines intersect the first plane; (k) the flexible tool further includes a support member and a push member, the support member has three spherical contact points in contact with the first flat surface, two spherical contact points in contact with the second flat surface contact points, the pushing member pushes the first flat surface and the second flat surface into contact with three spherical contact points and two spherical contact points respectively; (1) the rigid member includes a third flat surface substantially parallel to the first flat surface surface and a fourth flat surface substantially parallel to the second flat surface, and the pushing member includes a first member and a second member, the first member contacts the third flat surface to push the rigid member toward three spherical contact points, and the second member contacts a fourth flat surface to push the rigid member toward the two spherical contact points; (m) the flexible tool further includes a return mechanism configured to push the intermediate portion toward a predetermined starting position; (n) the return mechanism is an adjustable bend and The adjustable bend includes a ring; (o) the return mechanism includes an electromagnet; (p) the optical fiber is connected at the proximal end to an electronic device that detects the shape of the optical fiber by light transmitted through the optical fiber; and/or ( q) The flexible tool further includes a housing enclosing the adjustable bend and providing space within the housing for adjusting the adjustable bend.

One aspect of the present technology includes a method for detecting the shape of a flexible tool, the method comprising: disposing an optical fiber along at least a portion of the flexible tool, securing a first end of the optical fiber at or near an end of the tool, fixing the second end of the optical fiber at a known position, constraining a portion of the optical fiber between the first end and the second end to a single translational degree of freedom substantially along an axis defined by the optical fiber, moving at least the The end of the tool causes the tool to have a resultant shape, transmits light along the cable, and uses the transmitted light to detect the resultant shape of the flexible tool.

In an example, the optical fiber is arranged offset from and substantially parallel to the neutral axis of the flexible tool.

One aspect of the present technology includes a flexible tool comprising: an optical fiber comprising a proximal end, a distal end, an intermediate portion between the proximal end and the distal end, a an adjustable bend between the upper portion and the middle portion; and a housing enclosing the adjustable bend and providing space within the housing for adjusting the adjustable bend.

In an example, (a) the housing prevents contact with the adjustable bend from the outside of the flexible tool; (b) the adjustable bend includes at least one full loop; (c) the adjustable bend is less than one full loop; ( d) the housing provides clearance to allow relative bending and straightening of the adjustable bend; (e) the flexible tool is configured to bend a predetermined positive angle within the middle portion and a predetermined negative angle within the middle portion; and the clearance accommodating the entire range of relative bending and straightening within the adjustable bend caused by bending the flexible tool to predetermined positive and predetermined negative angles; (f) the space within the housing is sufficient to provide surrounding radial clearance around the entire perimeter of the adjustable bend; and/or (g) the space within the housing constraining the adjustable bend substantially in a plane.

Other aspects, features, and advantages of the technology will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which are a part of this disclosure and illustrate by way of example the principles of the technology.

Description of drawings

Figure 1 is an end cross-sectional view of a flexible tool with an optical fiber;

Figure 2 is a side view of a flexible tool with an optical fiber in a flat state;

Figure 3 is a side view of a flexible tool with an optical fiber in a bent state;

Figure 4 is a side view of the flexible tool with optical fibers in a bent state opposite to the bend in Figure 3;

Figure 5 is an exemplary illustration of position error of an optical fiber;

Figure 6 is a schematic representation of an optical fiber having a proximal end, a distal end and an intermediate portion;

Figure 7 is an exemplary illustration of a tool with an articulating joint;

Figure 8 is a first way of providing a single translational degree of freedom;

Figure 9 is a first view of a second way of providing a single translational degree of freedom;

Figure 10 is a second view of a second way of providing a single translational degree of freedom;

Figure 11 is a third view of the second way of providing a single translational degree of freedom;

Figure 12 is a fourth view of the second way of providing a single translational degree of freedom;

Figure 13 is a fifth view of the second way of providing a single translational degree of freedom;

Figure 14 is a schematic representation of an optical fiber having a proximal end, a distal end, and an intermediate portion, and an electromagnet;

Figure 15 is a first exemplary illustration of a housing enclosing an adjustable bend;

Figure 16 is a second exemplary illustration of a housing enclosing an adjustable bend;

Figure 17a is a third exemplary illustration of a housing enclosing an adjustable bend;

Fig. 17b is similar to Fig. 17a, but includes a section broken out so that the adjustable bend is more visible; and

18 is a fourth exemplary illustration of a housing enclosing an adjustable bend.

Detailed ways

The following description is provided with regard to several examples that may share common characteristics and characteristics. It should be understood that one or more features of any one example may be combined with one or more features of other examples. Additionally, any single feature or combination of features in any of the examples may constitute an additional example.

Throughout this disclosure, terms such as "first", "second", etc. may be used. However, these terms are not intended to be limiting or to indicate a particular order, but are used to distinguish similarly described features from each other unless expressly stated otherwise. Terms such as "substantially" and "about" are intended to allow for manufacturing tolerances, variations in measurement tolerances, or variations from ideal values that those skilled in the art will accept.

As discussed herein, a neutral axis refers to a line along a flexible body where the length does not change when the body bends. In a cylinder, the neutral axis coincides with the axis defining the center of the cylinder.

FIG. 6 is a schematic representation of an optical fiber 100 having a proximal end 104 , a distal end 106 and an intermediate portion 108 . The proximal end 104 may be fixed in place to provide a known position for calculating the shape of the optical fiber 100 . The intermediate portion may have a single degree of freedom of translation substantially along the axis defined by the optical fiber 100 at the intermediate portion 108 . This single degree of freedom is schematically shown by blocks 110 on two wheels 112 . Exemplary implementations for a single degree of freedom are described in detail below.

Optical fiber 100 includes an adjustable bend 114 between proximal end 104 and intermediate portion 108 . The adjustable bend 114 is shown as a ring, but a ring is not required, see eg FIG. 15 . The optical fiber 100 may be disposed within a body 116 having a flexible portion 118 and a free end 120 , such as the catheter 10 shown in FIG. 3 . Not all of the optical fibers 100 need be within the body 116 . For example, only the distal end 106 and the intermediate portion 108 may be located within the body 116 .

As shown in FIGS. 2-4 , the distal end 106 may be fixed relative to the free end 120 . In other words, when the body 116 moves, eg, when the flexible portion 118 bends, the distal end 106 and the free end 120 move together.

FIGS. 1-4 also illustrate the optical fiber 100 disposed within the body 116 and offset from the neutral axis 16 . By maintaining the relative position of the optical fiber 100 to the neutral axis 16 for a distance, the optical fiber 100 can be substantially parallel to the neutral axis. 3 and 4 show the optical fiber 100 equidistant from the neutral axis 16 through the flexible portion 118 . Thus, at least when the flexible portion 118 is straight, the optical fiber 100 is substantially parallel to the neutral axis 16 at the flexible portion.

The bends at the flexible portion 118 shown in FIGS. 3 and 4 must be two-dimensional because they are representations of three-dimensional objects in a two-dimensional medium, but it should be understood how bends can occur in either direction, which will result in both translational and rotational degrees of freedom. Furthermore, a third translational degree of freedom can be envisaged if the body 116 moves along the neutral axis. Additionally, the body 116 can twist about the neutral axis with a third rotational degree of freedom.

Although the main body 116 and the bend at the flexible portion 118 are shown as continuous, the bend may be an articulating joint 160 as shown in FIG. 7 .

Figure 8 shows a first way in which the intermediate portion 108 can be constrained to a single degree of freedom. FIG. 8 shows the rigid member 122 with the intermediate portion 108 constrained within an inner portion 124 shown as a bore along the central axis of the rigid member 122 .

As can be seen in Figure 8, the rigid member 122 is substantially in the form of a cylinder having a flat 126 formed along the axial length of the cylinder. The rigid member 122 is supported by a first cylindrical pin 128 and a second cylindrical pin 130 in contact with a cylindrical surface 138 of the rigid member. The rigid member is further supported along the flat 126 by a third cylindrical pin 132 and a ball 134 . Spring 136 urges rigid member 122 into contact with three pins 128 , 130 , 132 and ball 134 . Using this configuration, the rigid member, and thus the optical fiber 100 contained therein, can only move along the central axis of the rigid member 122, which results in a single translational degree of freedom. Although cylindrical pins are discussed throughout this document, part-cylindrical or part-cylindrical surfaces may also be used.

Using the configuration shown in FIG. 8 , rigid member 122 is constrained by three points of contact on flat 126 via third cylindrical pin 132 and ball 134 , and is constrained by first cylindrical pin 128 and second cylindrical pin 130 . Two contact points on the cylindrical surface 138 are constrained. On an ideal or perfectly created part, the third cylindrical pin 132 would make contact with the flat 126 along a line. However, due to the imperfect nature of manufactured parts, the flat portion 126 may not be perfectly flat, and the third cylindrical pin 132 may not be perfectly round. Therefore, the actual contact between the flat portion 126 and the third cylindrical pin 132 should be two or more points of contact along the line of contact that would exist if the part were perfectly manufactured. Thus, the contact between the flat portion 126 and the third cylindrical pin 132 is at least two points.

Using the three contact points on flat portion 126, rigid member 122 is constrained to move only in the plane defined by these three points. When the two points of contact between the rigid member 122 and the first cylindrical pin 128 and the second cylindrical pin 130 are added, the rigid member 122 is constrained to move in only a single translational degree of freedom. All spins are blocked.

Another exemplary way of achieving a single degree of freedom is shown in FIGS. 9-13 .

Figure 9 shows a perspective view of a block 140 constrained by a support member 142, shown as a rectangular prism having three pairs of parallel sides. The base 142 includes a first wall 144, a second wall 146, and push members shown as a first push member 148a and a second push member 148b. The first urging member 148a and the second urging member 148b are shown as U-shaped cantilever springs that urge the block 140 toward the first wall 144 and the second wall 146 . Any device intended to push block 140 toward first wall 144 and second wall 146 may be employed. For example, two coil springs may be employed or oriented so that a component of the applied force is directed towards the first wall 144 and a second component is directed towards the second wall 146 and the resultant vector of the two components is generally directed towards the first wall 144 and the second wall A single spring at the intersection of 146.

Fig. 10 is a top view different from Fig. 9 only in that the two spherical contact points 150a, 150b between the block 140 and the second wall 144 are visible. Similarly, FIG. 11 shows three spherical contact points 150c, 150d, 150e not visible in FIG. 9 . Figure 12 shows a cross-section taken through Figure 11 showing that the spherical contact point may be in the form of a ball. The balls may be fixed to provide sliding contact or allowed to roll and provide rolling contact. Figure 13 shows the support member 142 without the block 140, so that all spherical contact points 150a to 150e are visible. The rollers 150c , 150d , 150e provide three contact points along the bottom side of the block 140 and the spherical contact points 150a , 150b provide two contact points along the sides of the block 140 .

Using the configuration shown in these figures, mass 140 is constrained to move with a single translational degree of freedom parallel to both first wall 144 and second wall 146 . Accordingly, block 140 may correspond to middle portion 108 .

Both configurations shown provide an intermediate portion 108 with a single translational degree of freedom, and may provide configurations that minimize friction or drag due to the manner in which constraints are provided. With the aforementioned minimal constraints on degrees of freedom, potential mechanical interference can be minimized, and thus the force required to translate along a single degree of freedom can also be minimized. This can be advantageous because unnecessary force is not transferred to the fiber 100, and thus can reduce or minimize the strain introduced into the fiber, which can affect the fiber's ability to be used to accurately sense the shape of the tool.

Returning to FIG. 6 , the adjustable bend 114 may be used to measure the relative position between the proximal end 104 and the intermediate portion 108 using the shape sensing of the optical fiber 100 . Since the middle portion 108 is constrained to a single translational degree of freedom, the other five degrees of freedom are known. Thus, the adjustable bend 114 is capable of measuring the sixth degree of freedom (translational degree of freedom), such that all six degrees of freedom are known.

The adjustable bend 114 may also provide some spring-like restoring force and thus act as a return mechanism. The tendency of the adjustable bend 114 to return to a straight state can provide sufficient force to push the intermediate portion 108 to a predetermined starting position if the applied force constraining the intermediate portion 108 to a single degree of freedom is low enough. Accordingly, when the body 116 is manipulated and the intermediate portion 108 is pulled away from the predetermined starting position, the adjustable bend 114 can provide sufficient restoring force to return the intermediate portion 108 to the predetermined starting position.

Fig. 14 shows an alternative for pushing the middle part 108 to a predetermined starting position. Figure 14 is substantially the same as Figure 6 except for the addition of an electrical coil 152 and a soft iron or magnet 154 (eg, an electromagnet). Using this configuration, an electrical coil 152 and soft iron or magnet 154 can be used to apply force. Because the fiber optic 100 can provide a very sensitive measurement of the strain in the fiber and any buckling 156 that may occur, the current in the electrical coil 152 can be controlled based on the strain measurement so that the tension in the fiber 100 can be kept very low. Other implementations of the return mechanism are also possible. For example, springs (eg, coil springs) or pressurized gas (eg, air cylinders or air springs) may be used.

FIG. 15 shows the adjustable bend 114 within the housing 158, where the housing 158 is shown in cross-section. In this view, the adjustable bend 114 is shown as being less than a full loop and approximately in the middle of the space 160 on the interior of the housing 158 . Open space 160 includes an upper boundary 162 (ie, minimum bend radius) and a lower boundary 164 (ie, maximum bend radius), shown as surfaces, which may limit the amount of curvature of adjustable bend 114 . For example, upper boundary 162 and lower boundary 164 may constrain (eg, adjust) the degree to which adjustable bend 114 can become relatively more curved or relatively straighter. This adjustment can accommodate the distance D that the optical fiber 100 can move relative to the catheter 10 as described above with respect to FIGS. 3 and 4 . As shown, space 160, upper boundary 162, and lower boundary 164 together define a tall, narrow slot having an arcuate profile. However, any orientation of space 160 can be utilized. For example, instead of the space 160 being on the top, the space 160 could be on the bottom, on the side, or anywhere in between. Also, the space 160 can be in a form other than a slot. Any shape can be utilized that provides the desired protection for the adjustable bend 114 while allowing the adjustable bend 114 to bend in a manner that suits the measurement accuracy desired by the user. But certain properties of space 160 may offer advantages. For example, the tall, narrow slots shown may be more suitable for cleaning than a more expanded volume because the volume of space 160 can be minimized and less cleaning fluid will be required when cleaning for surgical use.

As shown in FIG. 15 , the adjustable bend 114 may be a gradual bend and/or a gentle bend, such as a relatively large bend radius. The gentler the bend, the more accurate the measurement with the optical fiber. However, relatively gentler bends will require more space than relatively less gradual bends. Thus, the size of the adjustable bend 114 and associated open space 160 can be optimized by trading measurement accuracy for size, and vice versa. If the adjustable bend 114 is sufficiently tapered (eg, as shown in FIG. 15 ), sufficiently accurate measurements can be achieved without constraining a portion of the fiber 100 to a single degree of freedom. Intermediate portion 108 as described herein may refer to any portion of optical fiber 100 between proximal end 104 and distal end 106 , at least where optical fiber 100 has no portions constrained to a single degree of freedom.

Preferably, the adjustable bend 114 does not contact either the upper boundary 162 or the lower boundary 164 as the optical fiber 100 and/or catheter 10 moves through the entire intended range of motion, such that the adjustable bend 114 does not "bottom out." . If the adjustable bend 114 contacts either the upper boundary 162 or the lower boundary 164 during movement, strain may be induced in the optical fiber 100 and affect measurement accuracy. To avoid this, clearance can be provided between the adjustable bend 114 and both the upper boundary 162 and the lower boundary 164 in the worst case (eg, maximum adjustment) scenario.

In FIG. 15, the adjustable bend 114 is approximately halfway between the upper boundary 162 and the lower boundary 164, which corresponds to the optical fiber 100 in its straight (or most straight) position. When the optical fiber 100 is bent together with the catheter 10 (or other flexible tool), the adjustable bend 114 will move toward one of the upper boundary 162 and the lower boundary 164, and thus the adjustable bend 114 will become relatively straight or Relatively curved.

FIG. 16 shows (in cross-section) another example of housing 158 that differs from FIG. 15 in that adjustable bend 114 is a complete loop (eg, 360°). Here, as the adjustable bend 114 is adjusted, the diameter of the bend will increase or decrease. Open space 160 is shown as generally circular, with lower boundary 162 being the radial surface of the open space. However, any convenient shape of the space may be chosen as long as the space satisfies other design considerations. If adjustable bend 114 is a complete loop, upper border 164 may not be required.

In Figure 16, the complete loop is oriented substantially vertically. In other words, the complete ring is substantially in a vertically oriented plane. However, any orientation of the rings can be chosen.

Figure 16 also shows a rigid member 122 that is substantially in the form of a cylinder having a flat portion 126 formed along the axial length of the cylinder. Flat 126 contacts a ball or cylindrical pin 166 (which may include another flat). Accordingly, rigid member 122 may be constrained to approximately one degree of freedom when moving within cylindrical channel 168 . All other methods described above of constraining the intermediate portion 108 to a single degree of freedom (see eg FIGS. 8-13 and associated descriptions) may be substituted for the method shown in FIG. 16 . If the fiber 100 has a section constrained to a single degree of freedom, the section constrained to a single degree of freedom can be used to calculate the shape and orientation of the fiber 100 between the single degree of freedom section and the distal end 106, simplifying the shape and orientation calculations and/or improve the accuracy of said calculations. The adjustable bend 114 can be used to calculate or measure the position of a part constrained to a single degree of freedom, where the orientation is known based on the single degree of freedom. The position and orientation of the optical fiber 100 from the single degree of freedom section up to and including the distal end 106 can then be calculated based on the position and orientation of the single degree of freedom section.

Figures 17a and 17b are similar to Figure 16, except that the adjustable bend 114 is in the form of a ring. Here, the ring is shown as horizontal and the open space 160 is not clearly defined. On the contrary, the open space makes use of unused open volumes. It is therefore also possible to have no distinct upper or lower boundary. Housing 158 may include a cover, not shown, so that the interior is visible. The proximal end 104 (not shown in this figure) can be fixed near the adjustable bend 114 and used as a reference position for calculating the shape of the optical fiber 100, or a single degree of freedom can be applied (as in FIGS. 9-13 ). and shown in Figure 16).

Figure 18 is similar to Figure 16, except that the adjustable bend 114 is substantially vertical. However, the adjustable bend 114 includes multiple complete loops. As shown, there are two full circles (eg 720°). Also, the open space 160 is shown with an upper boundary 162 (in the form of a cylinder bounding a minimum bend radius), but without a distinct upper boundary. In this configuration, the upper boundary also provides a support and/or positioning location for the adjustable bend 114 . Housing 158 may include a cover, not shown to allow visibility of the interior. This configuration can also be used with the single degree of freedom sections and/or fixed sections described above with respect to the proximal end 104 .

Including more than one complete loop may be advantageous because, for the distance D that the optical fiber 100 is moved, the diameter of the loop does not have to change as much as the diameter of a single loop. For example, assuming that the ring is a circle, the diameter of the ring (d) is related to the circumference (C) using the well known equation C=πd. If the ring needs to accommodate fibers that travel a distance D, the circumference will increase or decrease by D (C±D=πd). This causes the diameter of the circle to vary by ±D/π. However, in the case of two rings, the change is made on both rings, and thus the diameter only needs to be adjusted by ±D/2π. Increasing the number of rings to three will result in ±D/3π. Thus, the amount by which the diameter will change is inversely proportional to the number of rings, and more rings will require less space for adjusting the diameter, which can result in a more compact device.

For each implementation of the open space 160 described above, the amount of clearance around the adjustable bend 114 can be optimized based on several factors. If the adjustable bend 114 can be constrained to only allow movement in one plane (e.g., only in the x and y directions of a Cartesian coordinate system, but not in the z direction), then measurements made with the fiber optic 100 The accuracy of can be increased because any relevant calculations can take this limited motion into account. However, the application of such planar constraints may require contact with the fiber 100, which, in the presence of any associated friction, induces resistance that induces strain in the fiber. But this strain can change the calculations used to sense the shape of the fiber.

If a frictionless system is not practical, it may be feasible to provide clearance around the adjustable bend 114, which eliminates or substantially reduces contact between the adjustable bend 114 and the nearest wall. This can be achieved by providing a gap between adjacent walls that is larger than the diameter or thickness of the optical fiber 100 (e.g., the open space 160 within the housing 158 is sufficient to extend the entire length of the adjustable bend 114 along the predetermined length of the adjustable bend 114). provide radial clearance around the perimeter). With a limited amount of clearance, the adjustable bend 114 can be constrained to be substantially in-plane. For example, the adjustable bend 114 may be constrained to be substantially in-plane if the gap between adjacent walls is slightly greater than twice the thickness or diameter of the optical fiber 100 .

Each of the above-mentioned housings 158 can prevent contact with the adjustable bending portion 114 from the outside of the housing 158 . For example, a user will be prevented from inadvertently touching the adjustable bend 114 to deform the adjustable bend 114 to change the detected shape of the optical fiber 100 . Thus, the adjustable bend 114 can be adjusted solely or substantially solely due to changes in the distance D described above.

In each of the configurations discussed above, it may be preferable to prevent the axial strain in the fiber 100 from exceeding 500 microstrain, more preferably prevent it from exceeding 50 microstrain, and/or prevent the fiber 100 from having a bend of less than 0.3 inches The radius, more preferably prevents the optical fiber 100 from having a bend radius of less than 3 inches.

Although the technology has been described in connection with several practical examples, it should be understood that the technology is not limited to the disclosed examples, but on the contrary, the technology is intended to cover various modifications and equivalents included within the spirit and scope of the technology. layout.

Claims (29)

1. A flexible tool comprising: optical fiber, which includes proximal end, distal end, an intermediate portion between said proximal end and said distal end, an adjustable bend between said proximal end and said intermediate portion, wherein the intermediate portion is constrained to have a single degree of freedom of translation substantially along an axis defined by the optical fiber at the intermediate portion. 2. The flexible tool of claim 1 , further comprising a body including a flexible portion and a free end, wherein a portion of the optical fiber is located within the body, and the distal end is in the Fixed relative to the body at or near the free end. 3. The flexible tool of claim 2, wherein the body includes a neutral axis, and the optical fibers are disposed within the body offset from the neutral axis and substantially parallel at least at the flexible portion on the neutral axis. 4. The flexible tool of claim 2, wherein the distal end is movable in three translational degrees of freedom relative to the proximal end. 5. The flexible tool of claim 2, wherein the distal end is movable relative to the proximal end in two rotational degrees of freedom. 6. The flexible tool of claim 2, wherein the distal end is movable relative to the proximal end with three translational degrees of freedom and two rotational degrees of freedom. 7. The flexible tool of claim 2, wherein the flexible portion comprises a flexible joint. 8. The flexible tool of claim 1, further comprising a rigid member, wherein the intermediate portion is secured within the rigid member. 9. A flexible tool according to claim 8, wherein the rigid member is substantially a cylinder having a flat surface along the axial length of the cylinder. 10. The flexible tool of claim 9, further comprising: two cylindrical pins having central axes substantially parallel to each other and together defining a first plane, a third cylindrical pin having said central axes substantially parallel to said two cylindrical pins and extending from said said central axes of the two cylindrical pins are offset and substantially perpendicular to said first plane's central axis in a second plane, ball, and spring, where said third cylindrical pin and said ball contact said rigid member along said planar surface, said two cylindrical pins are in contact with said rigid member along said axial length of said cylinder rather than on said flat surface, and The spring contacts the rigid member to urge the rigid member into contact with the two cylindrical pins, the third cylindrical pin, and the ball. 11. The flexible tool of claim 8, wherein the rigid member comprises a block having a first planar surface defined by a first plane and a second planar surface defined by a second plane along substantially A line parallel to the single degree of freedom intersects the first plane. 12. The flexible tool according to claim 11, further comprising a support member having three spherical contact points in contact with the first flat surface, and a push member in contact with the second flat surface. Two spherical contact points, the pushing member pushes the first flat surface and the second flat surface into contact with the three spherical contact points and the two spherical contact points, respectively. 13. The flexible tool of claim 12, wherein the rigid member includes a third planar surface substantially parallel to the first planar surface and a fourth planar surface substantially parallel to the second planar surface, And the pushing member includes a first member contacting the third flat surface to push the rigid member toward the three spherical contact points, and a first member contacting the fourth flat surface to push the rigid member toward the two spherical contact points. A second member with a spherical contact point. 14. The flexible tool of claim 1, further comprising a return mechanism configured to urge the intermediate portion toward a predetermined starting position. 15. The flexible tool of claim 14, wherein the return mechanism is the adjustable bend, and the adjustable bend includes a loop. 16. The flexible tool of claim 14, wherein the return mechanism comprises an electromagnet. 17. The flexible tool of claim 1, wherein the optical fiber is connected at the proximal end to an electronic device that detects the shape of the optical fiber by transmitting light through the optical fiber. 18. The flexible tool of claim 1, further comprising a housing enclosing the adjustable bend and providing space within the housing for adjustment of the adjustable bend. 19. The flexible tool of claim 1, further comprising: a body comprising a flexible portion and a free end, wherein a portion of the optical fiber is located within the body, and the distal end is fixed relative to the body at or near the free end, a return mechanism configured to push the intermediate portion towards a predetermined starting position, and Rigid members, of which, said intermediate portion is secured within said rigid member, the body includes a neutral axis, and the optical fiber is disposed within the body offset from the neutral axis and substantially parallel to the neutral axis at least at the flexible portion, the distal end is movable relative to the proximal end with three translational degrees of freedom and two rotational degrees of freedom, and The optical fiber is connected at the proximal end to an electronic device that detects the shape of the optical fiber by transmitting light through the optical fiber. 20. A method for detecting the shape of a flexible tool, the method comprising: providing an optical fiber along at least a portion of the flexible tool, securing the first end of the optical fiber at or near the end of the tool, securing the second end of the optical fiber at a known position, constraining a portion of said optical fiber between said first end and said second end to a single degree of translational freedom substantially along an axis defined by said optical fiber, moving at least said end of said tool such that said tool has a resulting shape, transmit light along the cable, and The resulting shape of the flexible tool is detected using the transmitted light. 21. The method of claim 20, wherein the optical fiber is arranged offset from and substantially parallel to the neutral axis of the flexible tool. 22. A flexible tool comprising: optical fiber, which includes proximal end, distal end, an intermediate portion between said proximal end and said distal end, an adjustable bend between the proximal end and the intermediate portion; and A housing encloses the adjustable bend and provides space within the housing for adjustment of the adjustable bend. 23. The flexible tool of claim 22, wherein the housing prevents access to the adjustable bend from an exterior of the flexible tool. 24. The flexible tool of claim 22, wherein the adjustable bend comprises at least one full loop. 25. The flexible tool of claim 22, wherein the adjustable bend is less than one full loop. 26. The flexible tool of claim 22, wherein the housing provides clearance to allow relative bending and straightening of the adjustable bend. 27. The flexible tool according to claim 26, wherein the flexible tool is configured to bend a predetermined positive angle within the intermediate portion and a predetermined negative angle within the intermediate portion; and the gap accommodates through The entire range of relative bending and straightening within the adjustable bend caused by bending the flexible tool by the predetermined positive angle and the predetermined negative angle. 28. The flexible tool of claim 22, wherein the space within the housing is sufficient to provide radial clearance around the entire perimeter of the adjustable bend along a predetermined length of the adjustable bend. 29. The flexible tool of claim 22, wherein the space within the housing constrains the adjustable bend to be substantially in-plane.